Red tailed hawk

I saw three large birds flying below the hill where I was, two were brown color but the third was white and was ahead of the other two. It did not seem they were fighting. I saw them only a few seconds before losing sight. It seem they were all Red tailed hawks but the white one with a condition called Leucism in which there is partial loss of pigmentation in an animal resulting in white, pale, or patchy coloration of the skin, hair, feathers, scales or cuticle, but not the eyes. See the reference.